Reduce “flapping” in silnylon shelters

Like an inverted v setup mid users use quite often to gain more livable space by getting the pole out of the middle. And most use a pair of poles so why not use them both to increase the strength of your structure. Win, win.

Precisely. I don't necessarily like the idea of putting the other pole on an angle, as I've found that for my own setup, it compromises vertical strength to too great an extent. That being said, why not use anything and everything at your disposal to increase the seaworthiness of your shelter? This of course got me thinking down the rabbit-hole, and I realized that filling your (framed) pack with full water bottles and leaning it against the shelter wall can also provide a mid-surface point of support to decrease flapping.

On other side benefit of additional bracing is that with less flapping, less condensation falls onto your bag during the night. Actually that might be the most important benefit of all, as the other ones are merely annoying inconveniences, rather than actual bad situations.

Pole is stronger for the weight when there's one pole vertical.

If you have two poles of the same total weight, they will each be half the diameter, but the strength is the square of the diameter, so each will be 1/4 as strong, and since there are two, together they're half as strong.

Plus, for the same peak height, if the pole is at an angle, it will be longer, so it will be heavier, plus it's strength is less because it's longer so it will bend more.

If you have an inverted V, and you push down on the two poles, they'll tend to bow outward and won't be so strong.

But, if it stops flapping and provides more floor space, a little extra weight of pole may be worth it. And if you're using trekking poles you have anyway, then it doesn't weigh anything extra.

I know what you mean about pyramid flapping in the wind. Noisy.

Maybe it actually puts less force on tent stake – spreads the force over a period of time – like having an elastic cord guyline. The only time a tent stake pulled out was when it was in real sandy soil – I should have put a rock on it.

I made a cuben pyramid but the issues you described are not limited to silnylon. I designed my shelter to use two trekking poles exactly as you describe. The only difference is that I reversed the pole and put the tip in the ground. It gives a better bite, the handle isn't in the dirt and it it easier to protect the shelter fabric from the handle than the basket and tip.

In high winds the pulled out side is supported by the trekking pole and I believe adding a good bit of strength to the system. The key for me was getting the two trekking pole handle tight up in the peak which took some trial and error.

A good idea Kevin, one I'll have to try.

I don't think there's any way to eliminate deflection entirely in such shelters, but good design can certainly minimize it. The BD Megalight is a big offender in the flapping arena, while the Trailstar, Solomid, and Seek Outside BT2 are noteably still and quiet.

Using short guylines, or even staking out through the webbing loops directly, also helps to reduce flapping. This greatly reduces or eliminates movement perpendicular to the pull of the guylines which keeps the fabric panels in place.

Many UL shelters aren't good in the wind:flat panels flap. Other than design, a taut pitch, site selection and orientation to the wind are all you have to work with.

I reduce sag and ensure continual tautness of my silnylon tent by using lengths of surgical tubing. They are sold in fishing gear stores as "snubbers". They have hardware on both ends that make it easy to attach to tent lines. They are good for having a tent survive super strong gusty winds, because the tent can flex a bit, but comes back to shape after the gust.

Blog post: http://backpackingtechnology.com/tents/shock-cords-for-tent-lines/

Give you head room. Heavy rocks as anchors to pull it away to increase tent space. They need to be on the lower third of the tent.

Climbers on porta-ledges use an extra long thin tent pole that runs from the two bottom corners next to the cliff up to the middle of the opposite side wall to get extra space too on half pyramid shaped shelters.

The pattern cut of the pyramid has a lot to do with the flapping or lack of. Hex shaped shelters are harder to cut the pattern properly.